1. Field of the Invention
This invention relates to an air circulation system for thermostatic chambers.
2. Description of the Prior Art
There are available conventional burner apparatuses for thermostatic chambers mounted on vehicles, such as one disclosed in the Japanese Patent Application Laid-Open No. 211118/1986. This burner apparatus is described below by referring to FIGS. 6 and 7.
In FIG. 6 showing the burner apparatus 60 for the vehicle's thermostatic chamber, an intake manifold of the internal combustion engine 61 and an air cleaner 63 are connected through an air intake pipe 62. There is a bypass pipe 64 installed in the middle of the air intake pipe 62. The bypass pipe 64 is connected to a burner 65, downstream of which is installed a heat exchanger 66. Air heated by the heat exchanger 66 is supplied through a supply pipe 69 and discharged from a hot air blowing outlet 68 into the thermostatic chamber 67.
FIG. 7 shows the outline of the burner apparatus 60 for the vehicle's thermostatic chamber. External air is taken in from the air intake port and introduced through the air cleaner 63 and a blower 77 and then through an air intake port 79 into the heat exchanger 66 where it is heated by hot gas from the burner 65. The heated air is now delivered from an air delivery outlet 80 into the supply pipe 69. The burner 65 has an atomizing plug 75 connected to a fuel supply device 74, and a firing plug 76. A controller 70 receives a temperature signal from a temperature sensor 78 in the thermostatic chamber 67 to control the burner 65. In the figure, reference numeral 71 denotes an operation switch of the controller 70, 72 a battery, 73 a fuel tank, and 81 a blower.
The burner apparatus for the vehicle's thermostatic chamber using the abovementioned heat exchanger as shown in FIGS. 6 and 7 can quickly atomize the liquid fuel and burn it by means of ignition the rapid atomizing system and the rapid ignition system to efficiently heat the circulating air by the burning gas and supply clean hot air with no burned gas contained into the chamber. The burner apparatus, however, has yet to be improved with respect to the ability to effectively and powerfully blow the hot air into the thermostatic chamber, increase the amount of circulating air, maintain a uniform temperature distribution in the chamber, and prevent reduction in temperature in the chamber as a result of the hot air escaping from the chamber when the door is open.